there’s a guy in my area who runs a successful “bike doctor” business.
Bascially, he’s Cytech qualified and has a van which is kitted out with a mobile workshop.
His prices are extremely competitive because he doesn’t have large permises to rent etc (although he does use another workshop at his house for some jobs).
It has been an absolute dream for me. I don’t have the time to get to an LBS. So he’s “on call” if I need a headset pressed before the weekend, or a mount faced for example.
Or if I want/need something done to my bike before a weekend away and just don’t have the time (i.e. fitting of a new chainguide and sorting out gears etc), then he will come and pick the bike up, do the work and then drop it back off again.
He also does visits to various office buildings. So people who cycle to work (and perhaps don’t have great maintenance skills) can have their bike worked on while they are working in the office, cycling home on a freshly serviced bike.
With CRC/Wiggle etc being so popular now, there are a lot of people buying parts and trying to fit them at home, rather than buying them from an LBS and getting the shop to fit it.
It won’t make you a millionaire, and isn’t very scaleable, but it’s cheap entry to the market, allows you to play with bikes all day, quite easy to sell (cheaper than LBS, word of mouth in cycling community, turn up to race days etc) and if it all goes boobies up, sell the van and tools and you’ve not lost a huge amount.